The purpose of this study is to examine the effect of two different physical exercise protocols on changes in coronary artery plaque composition and development of in-stent restenosis in patients treated with percutaneous coronary intervention with stent implantation. The investigators will compare aerobic interval training and moderate continuous training. Both exercise protocols have a duration of 12 weeks. The investigators hypothesize that aerobic interval training is superior to moderate continuous training regarding effects on the composition of coronary artery plaques and a reduction in the development of in-stent restenosis.